Mössbauer characterization of ¹¹⁹Sn⁴⁺ Dopant ions in the antiferromagnetic ilmenite NiTiO₃

P. Fabritchnyi (1) , Alain Wattiaux (2) , M. V. Korolenko (1) , Claude Delmas (2)

1 Department of Chemistry, Lomonosov Moscow State University
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Magnetic hyperfine splitting of the ¹¹⁹Sn⁴⁺ nuclear levels in the antiferromagnetic NiTiO₃ was for the first time observed using the Mössbauer effect. For the majority of the ¹¹⁹Sn⁴⁺ dopant ions, the saturation value of the transferred hyperfine field (at 4.2 K, H = 5.25 T) is found to be equal to that previously reported for ¹¹⁹Sn⁴⁺ in the antiferromagnetic MnTi0₃. This finding shows that in both ilmenites the spin polarization of Sn⁴⁺ is produced by the divalent cation half-filled e²_g orbitals involved in interlayer superexchange interactions and implies the location of the dopant within titanium (111) layers. The principal V_zz component of the EFG at the Sn⁴⁺ site in NiTiO₃ is found to have a positive sign and be aligned along the [111] axis, as it was the case for Sn⁴⁺ in MnTiO₃. Lattice-sum calculations on the basis of a simple ionic point-charge model, lead to an erroneous result (in either titanate the sign of V_zz on the Ti⁴⁺ site would be negative) and thus demonstrate their failure in identifying the Sn sites.

Mots clés: Antiferromagnetic materials; Nickel titanates; Point charge approximation; Electric field gradients; Superexchange interactions; Spin polarization; Hyperfine magnetic field; Hyperfine splitting; Doping; Mössbauer effect

Domaines: Matériaux

P. Fabritchnyi, Alain Wattiaux, M. V. Korolenko, Claude Delmas. Mössbauer characterization of ¹¹⁹Sn⁴⁺ Dopant ions in the antiferromagnetic ilmenite NiTiO₃. Solid State Communications, 2009, 149 (37-38), pp.1535-1538. ⟨10.1016/j.ssc.2009.06.002⟩. ⟨hal-00440449⟩